Performance Evaluation of Newly Developed Korean Antimicrobial Susceptibility Testing Panels for MicroScan System Using Clinical Isolates from Teaching Hospitals in Korea / 대한임상미생물학회지

BACKGROUND: Antimicrobial resistant continues to pose a threat to public health. Therefore, rapid and accurate antimicrobial susceptibility testing is very important. The objectives of this study were to evaluate the performance of the MicroScan system (Beckman Coulter, USA) with newly developed Korean Antimicrobial Susceptibility Testing Panels (KSCM panels) for antimicrobial susceptibility testing (AST) against clinical isolates in South Korea. METHODS: Three KSCM panels were designed in this study. For the performance evaluation, a total of 1,325 clinical isolates including 1,027 of Gram-negative bacilli and 298 Gram-positive cocci collected from eight general hospitals in South Korea were used. The results by KSCM panels were compared with those by conventional methods. RESULTS: By KSCM-1 panel for Gram-positive cocci, the rates of categorical agreement (CA) were >90% in all the antimicrobials tested in this study. The rates of major error (ME) were also 90%, ME rates <3%, and VME rates <1.5%. CONCLUSION: The newly developed three KSCM panels for MicroScan system (Beckman Coulter) showed excellent performance in AST against a large number of clinical isolates, and they are applicable to clinical microbiology laboratories.

Performance Evaluation of SENTiFIT 270 and FOB Gold Reagent for Detecting Fecal Occult Blood / 대한임상미생물학회지

BACKGROUND: Fecal occult blood tests have been widely used to screen for colorectal cancer. SENTiFIT 270 (Sentinel diagnostics, Italy) is a fecal occult blood test with an immunochemical method that utilizes FOB Gold reagents. We evaluated the performance of SENTiFIT 270 using the FOB Gold reagent. In addition, FOB Gold was evaluated with the HITACHI 7180 (Hitachi Ltd., Japan). METHODS: The precision and linearity of the SENTiFIT 270 was evaluated in accordance with applicable Clinical and Laboratory Standard Institute guidelines. The comparison study between SENTiFIT 270-FOB Gold and the OC-Sensor (Eiken chemical Co., Japan) was performed using stool specimens. RESULTS: In the precision evaluation, the total precision of SENTiFIT 270-FOB Gold was 4.94% and 2.54% at high and low concentrations, respectively. The HITACHI 7180-FOB Gold had excellent precision of 4.60% and 2.09% at high and low concentrations, respectively. Linearity was also excellent for the SENTiFIT 270-FOB Gold and HITACHI 7180-FOB Gold at 0.9987 and 0.9986, respectively. The SENTITIF 270-FOB Gold showed excellent agreement with a kappa value of 0.830 and a concordance rate of 93.6%. The HITACHI 7180-FOB Gold showed high agreement with a kappa value of 0.832 and a concordance rate of 93.9%. CONCLUSION: The SENTiFIT 270-FOB Gold showed excellent performance in accuracy, linearity, and comparative inspection ability.

Annual Report on External Quality Assessment Scheme for Clinical Microbiology in Korea (2014)

Annual proficiency surveys were performed in March, June and September 2014 by clinical microbiology division of The Korean Association of Quality Assurance for Clinical Laboratory. Parasitology part has been newly incorporated in this survey. For each trial, three sets which were composed of different combinations of five bacteria and yeast were distributed for gram stain, culture, identification, and antimicrobial susceptibility tests of general bacteriology and five fixed sputum smear on slides were distributed for acid fast bacilli stain. Two advanced bacteriology survey materials for culture and identification of anaerobic bacteria and mold were distributed to the voluntary participants in every trial and five mycobacterial culture and identification specimens, five anti-tuberculosis susceptibility testing specimens, and two Mycobacterium tuberculosis strains for rapid detection of rifampin and isoniazid resistance were distributed to the voluntary participants in March and June trials. Five virtual microscopic slides for stool parasite examination were open for the registered participants in June trial. A total of 340 laboratories were enrolled and 330 (97.0%), 331 (97.4%), and 331 (97.4%) returned the results on trial I, II, and III, respectively. For bacterial identification, the percent acceptable identification of Burkholderia cepacia, Klebsiella pneumoniae, Streptococcus pyogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pneumoniae, Streptococcus agalactiae, Plesiomonas shigelloides, and Enterococcus faecalis were greater than 95%. Group C and group D Salmonella species challenged as the different sets of M1422 resulted in the acceptable rate lower than 95% because nine participants reported the identification of different sets. Surveillance cultures for methicillin-resistant S. aureus and vancomycin-resistant enterococci were correctly determined by 89.6% and 69.0% of the respondents, respectively. Correct identification to species level of Candida albicans, Candida auris, Candida glabrata, and Candida parapsilosis were 86.1%, 1.6%, 48.1%, and 83.8%. Vancomycin disk diffusion test in S. aureus, missing oxacillin screen or penicillin susceptibility test in S. pneumoniae and lack of reliable methods of quinolone resistance detection in Salmonella species caused unacceptable results in antimicrobial susceptibility testing. Advanced bacteriology trials revealed low performance in species identification of mold. Mycobacterial culture, identification and susceptibility test performance was kept in excellence. The performance of identification of stool parasites was acceptable >90% for detection of helminth eggs and amebic cysts but 28.6% false positive responses resulted from negative specimens. In conclusion, species-level identification of fungi of both candida species and mold were challenging to clinical microbiology laboratories. Vancomycin disk diffusion method for S. aureus and lack of proper penicillin susceptibility test for S. pneumoniae were still common cause of inaccurate results. Virtual microscopic survey has been successfully introduced in parasitology.

Detection of Carbapenemases in Clinical Enterobacteriaceae Isolates Using the VITEK AST-N202 Card

BACKGROUND: The rapid and accurate detection of carbapenemase-producing Enterobacteriaceae (CPE) in clinical microbiology laboratories is essential for the treatment and control of infections caused by these microorganisms. This study was performed to evaluate the ability of the VITEK AST-N202 card to detect CPE isolates. MATERIALS AND METHODS: A total of 43 (Klebsiella pneumoniae, n = 37; Escherichia coli, n = 3; and Enterobacter cloacae, n = 3) CPE isolates and 79 carbapenemase-non-producing Enterobacteriaceae (CNE) isolates were included in this study. The CPE isolates harbored KPC-2 (n = 11), KPC-3 (n = 20), GES-5 (n = 5), VIM-2 (n = 2), IMP-1 (n = 1), NDM-1 (n = 2), or OXA-232 (n = 2). Of the 79 CNE isolates, eight K. pneumoniae isolates were resistant to ertapenem, imipenem, and meropenem, while the remaining 71 isolates were susceptible to the carbapenems. Antimicrobial susceptibilities were tested using the VITEK AST-N202 card, and the results were interpreted as positive when the isolates showed resistant or intermediate results. Modified-Hodge tests (MHTs) were performed using ertapenem or meropenem disks for the screening of carbapenemase production. Polymerase chain reaction (PCR) and direct sequencing were used to identify beta-lactamase genes. RESULTS: Sensitivity of MHT with ertapenem and meropenem disks for the detection of carbapenemase was 81.4% (35/43) and 81.4% (35/43), respectively, and a combination with both antibiotic disks increased the sensitivity to 88.4% (38/43). Specificity of the MHT was 100% (79/79) for the CNE isolates. Sensitivity of ertapenem, imipenem, and meropenem as assessed by the VITEK AST-N202 card was 100% (43/43), 93% (40/43), and 95.3% (41/43), respectively. Specificity (89.8%, 71/79) of the test with each carbapenem was improved to 100% (71/71) when eight carbapenem-resistant CNE isolates were excluded from the testing. CONCLUSION: The VITEK AST-N202 card showed high sensitivity for the detection of carbapenemases in Enterobacteriaceae strains. PCR and sequencing experiments for the detection of carbapenemases are recommended when clinical Enterobacteriaceae isolates show non-susceptibility to carbapenems.

Evaluation of Blood Culture System for Culture of Body Fluids / 임상검사와정도관리

BACKGROUND: Invasive and life-threatening infections such as meningitis, pericarditis, peritonitis, empyema, and septic arthritis are diagnosed via culture of relevant body fluids (BFs). The blood culture system (BCS) has been reported to be a useful alternative for BFs culture to enhance recovery of fastidious microorganisms and reduce detection time. The aim of this study was to evaluate the diagnostic performance of BCS as compared to conventional culture method (CCM) in terms of culture yield. METHODS: The samples collected between October 2011 and September 2012 were processed using CCM, while those collected between October 2012 and September 2013 were processed using BCS. The 2 processes were compared in terms of total number of requests, recovery rate, turnaround time (TAT), and detection time. RESULTS: The positive rate using CCM was 18.2% (575/3,151), where 845 isolates were recovered from 575 specimens. Using BCS, the positive rate was 28.3% (922/3,260), where 1,472 isolates were recovered from 922 specimens. While comparing the 2 methods on terms of yield of clinically significant isolates, a greater number of fungi (1.2%) and anaerobic bacteria (1.4%) were recovered using BCS as compared to using CCM. The difference in TAT for positive samples was 24 hours and 40 minutes, where BCS had a shorter TAT than CCM. The mean detection time of 951 positive samples by BCS was 19 hours and 56 minutes. Growth of clinically significant isolates was detected within 24 hours. CONCLUSIONS: BCS for culture of BFs showed an improvement in recovery rate, number of isolates, and TAT as compared to CCM. Thus, BCS is a suitable alternative for culture of BFs.

The Relationship Among Obesity, Benign Prostatic Hyperplasia and Erectile Dysfunction in Korea Men

PURPOSE: Pathogenically, both erectile dysfunction (ED) and benign prostatic hyperplasia (BPH) are closely related to vascular problems, and vascular problems are closely associated with obesity. This study evaluated the relationships between obesity, BPH, and ED. MATERIALS AND METHODS: The medical history of male patients, aged > or =40 years, evaluated at urology outpatient clinics of 11 university hospitals in Korea with chief complaints of lower urinary tract symptoms (LUTS)/BPH and ED were retrospectively evaluated. The correlations of medical history, body mass index (BMI), international prostate symptom score (IPSS), prostate volume, International Index of Erectile Function -5 (IIEF-5), and serum testosterone level were assessed. RESULTS: Body mass index showed significant correlations with IPSS (r=0.087, p=0.003), prostate volume (r=0.384, p<0.001), IIEF (r=-0.072, p=0.015), and serum testosterone concentration (r=-0.303, p<0.001). CONCLUSIONS: Body mass index correlates with testosterone concentration, prostate volume, and markers of LUTS and ED in men with the latter conditions.

Epidemiology and Characteristics of Metallo-beta-Lactamase-Producing Pseudomonas aeruginosa

Metallo-beta-lactamase-producing Pseudomonas aeruginosa (MPPA) is an important nosocomial pathogen that shows resistance to all beta-lactam antibiotics except monobactams. There are various types of metallo-beta-lactamases (MBLs) in carbapenem-resistant P. aeruginosa including Imipenemase (IMP), Verona integron-encoded metallo-beta-lactamase (VIM), Sao Paulo metallo-beta-lactamase (SPM), Germany imipenemase (GIM), New Delhi metallo-beta-lactamase (NDM), Florence imipenemase (FIM). Each MBL gene is located on specific genetic elements including integrons, transposons, plasmids, or on the chromosome, in which they carry genes encoding determinants of resistance to carbapenems and other antibiotics, conferring multidrug resistance to P. aeruginosa. In addition, these genetic elements are transferable to other Gram-negative species, increasing the antimicrobial resistance rate and complicating the treatment of infected patients. Therefore, it is essential to understand the epidemiology, resistance mechanism, and molecular characteristics of MPPA for infection control and prevention of a possible global health crisis. Here, we highlight the characteristics of MPPA.

Factors Influencing the False Positive Signals of Continuous Monitoring Blood Culture System / 대한임상미생물학회지

BACKGROUND: The false positive signals of a continuous monitoring blood culture system (CMBCS) increase the reporting time and laboratory cost. This study aimed to determine the highly relevant variables that discriminate false positive signals from true positive signals in a CMBCS. METHODS: Among 184,363 blood culture sets (aerobic and anaerobic), the signal-positive samples according to a BACTEC FX system (Plus Aerobic/F, BDA; Plus Anaerobic/F, BDN) and BacT/Alert 3D system (Standard Aerobic, BSA; Standard Anaerobic, BSN) between April 2010 and November 2013 were classified into two groups: false positive or true positive signals. The data of 15 parameters between the two groups were then statistically compared. RESULTS: Among total blood cultures, the positive rates of CMBCS signals according to BDA, BDN, BSA, and BSN were 4.9%, 2.8%, 3.8%, and 3.2%, respectively. The false positive rates of CMBCS signals according to BDA, BDN, BSA, and BSN were 0.6%, 0.1%, 0.1%, and 0.1%, respectively. The blood volume, detection time, time interval between admission and test, C-reactive protein concentration, leukocyte count, delta neutrophil index, and mean peroxidase index showed statistically significant differences between the two groups. CONCLUSION: There were no variables with diagnostic sensitivity and specificity for discriminating the two groups. Therefore, analysis of bacterial growth curves produced by CMBCS is needed for early and effective detection of false positive signals.

Annual Report on External Quality Assessment Scheme in Clinical Microbiology in Korea (2013) / 임상검사와정도관리

Annual external quality assessment was performed three times for clinical microbiology division of The Korean Association of Quality Assurance for Clinical Laboratory. For each trial, three sets composed of different combinations of four bacteria and one yeast were distributed for culture, identification, and antimicrobial susceptibility tests. A total of 340 laboratories were enrolled and 330 (97.0%), 331(97.4%), and 331(97.4%) returned the results on trial I, II, and III, respectively. For bacterial identification, the correct identification of gram-negative bacilli, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus capitis, Streptococcus agalactiae, Listeria monocytogenes, and Candida species was greater than 95%. However, correct identification of Staphylococcus lugdunensis, Corynebacterium striatum, Vibrio vulnificus, Aeromonas hydrophila, Cryptococcus neoformans, and Malassezia pachydermatis was relatively less accurate, with values of 95.4%, 89.9%, 50.7%, 91.3%, 93.6%, and 93.9%, respectively. Surveillance cultures for vancomycin-resistant enterococci and methicillin-resistant S. aureus were correctly determined by 95.4% and 93.9% of the respondents, respectively. False carbapenem-resistance due to AmpC beta-lactamase, disk diffusion testing for vancomycin in Staphylococcus species, oxacillin and penicillin susceptibility testing in S. lugdunensis and false imipenem-resistance in Proteus species were common sources of inaccurate results. The accuracy of species identification for Corynebacterium species and Vibrio species requires improvement. Consistent problems occurred with antimicrobial susceptibility testing of vancomycin for Staphylococcus species using the disk diffusion method.

Annual Report on External Quality Assessment Scheme in Clinical Microbiology in Korea (2013) / 임상검사와정도관리

Annual external quality assessment was performed three times for clinical microbiology division of The Korean Association of Quality Assurance for Clinical Laboratory. For each trial, three sets composed of different combinations of four bacteria and one yeast were distributed for culture, identification, and antimicrobial susceptibility tests. A total of 340 laboratories were enrolled and 330 (97.0%), 331(97.4%), and 331(97.4%) returned the results on trial I, II, and III, respectively. For bacterial identification, the correct identification of gram-negative bacilli, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus capitis, Streptococcus agalactiae, Listeria monocytogenes, and Candida species was greater than 95%. However, correct identification of Staphylococcus lugdunensis, Corynebacterium striatum, Vibrio vulnificus, Aeromonas hydrophila, Cryptococcus neoformans, and Malassezia pachydermatis was relatively less accurate, with values of 95.4%, 89.9%, 50.7%, 91.3%, 93.6%, and 93.9%, respectively. Surveillance cultures for vancomycin-resistant enterococci and methicillin-resistant S. aureus were correctly determined by 95.4% and 93.9% of the respondents, respectively. False carbapenem-resistance due to AmpC beta-lactamase, disk diffusion testing for vancomycin in Staphylococcus species, oxacillin and penicillin susceptibility testing in S. lugdunensis and false imipenem-resistance in Proteus species were common sources of inaccurate results. The accuracy of species identification for Corynebacterium species and Vibrio species requires improvement. Consistent problems occurred with antimicrobial susceptibility testing of vancomycin for Staphylococcus species using the disk diffusion method.

First Report of Nocardia farcinica Bursitis in a Patient with Diabetes Mellitus

No abstract available.

Molecular Characteristics of blaOXA-23-Producing Acinetobacter baumannii Isolated from a University Hospital / 대한임상미생물학회지

BACKGROUND: Multi-drug resistant (MDR) Acinetobacter baumannii has emerged as a significant infectious agent in hospitals worldwide. The purpose of this study was to determine the molecular characterization of MDR A. baumannii clinical isolates. METHODS: Two hundred eighty-five strains of non-duplicated A. baumannii collected from March to November 2011 from a university hospital laboratory located in the Wonju area of the Gangwon province of Korea were analyzed for MDR genes. RESULTS: All of the 285 imipenem-resistant A. baumannii isolates were encoded by a blaOXA-23-like gene, and all isolates with the blaOXA-23-like gene had the upstream element ISAba1. The 16S rRNA methylase gene armA was detected in 153 (50.2%) clinical isolates, but rmtA, rmtB, rmtC, rmtD and npmA were not detected in any isolates in the present study. The gene encoding aac(6')-Ib was the most prevalent aminoglycoside-modifying enzyme. The sequencing data for the quinolone resistance-determining region of gyrA and parC revealed the presence of Ser (TCA) 83 to Leu (TTA) and Ser (TCG) 80 to Leu (TTG) substitutions. All but one of the 285 A. baumannii isolates showed similar band patterns on repetitive extragenic palindromic-PCR profiles. CONCLUSION: The molecular characteristics of the resistance genes of MDR A. baumannii isolates obtained from the Wonju area of Gangwon province were similar to those of other areas in Korea.

The Prevalence of Vaginal Microorganisms in Pregnant Women with Preterm Labor and Preterm Birth

BACKGROUND: To investigate the risk factors for vaginal infections and antimicrobial susceptibilities of vaginal microorganisms among women who experienced preterm birth (PTB), we compared the prevalence of vaginal microorganisms between women who experienced preterm labor (PTL) without preterm delivery and spontaneous PTB. METHODS: Vaginal swab specimens from 126 pregnant women who experienced PTL were tested for group B streptococcus (GBS), Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma urealyticum, Chlamydia trachomatis, Trichomonas vaginalis, Neisseria gonorrhoeae, Treponema pallidum, herpes simplex virus (HSV) I and II, and bacterial vaginosis. A control group of 91 pregnant women was tested for GBS. Antimicrobial susceptibility tests were performed for GBS, M. hominis, and U. urealyticum. RESULTS: The overall detection rates for each microorganism were: U. urealyticum, 62.7%; M. hominis, 12.7%; GBS, 7.9%; C. trachomatis, 2.4%; and HSV type II, 0.8%. The colonization rate of GBS in control group was 17.6%. The prevalence of GBS, M. hominis, and U. urealyticum in PTL without preterm delivery and spontaneous PTB were 3.8% and 8.7% (relative risk [RR], 2.26), 3.8% and 17.3% (RR, 4.52), and 53.8% and 60.9% (RR, 1.13), respectively, showing no significant difference between the 2 groups. The detection rate of M. hominis by PCR was higher than that by culture method (11.1% vs. 4.0%, P=0.010). The detection rates of U. urealyticum by PCR and culture method were 16.7% and 57.1%, respectively. CONCLUSIONS: There was no significant difference in the prevalence of GBS, M. hominis, and U. urealyticum between the spontaneous PTB and PTL without preterm delivery groups.

Interleukin-1beta, Calcium-Sensing Receptor, and Urokinase Gene Polymorphisms in Korean Patients with Urolithiasis

PURPOSE: There are various causes of ureter calculi, and genetic factors are known to play a role. Interleukin-1beta (IL-1beta) and calcium-sensing receptor (CaSR) genes are related to hypercalciuria, and urokinase is related to the formation of calcium oxalate stones. This study investigated polymorphisms in IL-1beta, CaSR, and urokinase in patients with urolithiasis and healthy controls. MATERIALS AND METHODS: Urolithiasis patients treated at Chung-Ang University Hospital were enrolled from January 2007 to December 2008. The control group of volunteers displayed normal urinalysis findings in the health screening, no stones identified by ultrasonography, and no history of urolithiasis. DNA extracted from peripheral blood was analyzed by the polymerase chain reaction. Patients were genetically screened for mutations in IL-1beta (484 urolithiasis patients, 208 controls), CaSR (433 urolithiasis patients, 197 controls), and urokinase (370 urolithiasis patients, 167 controls). Stone metabolic study was done to see the differences between the metabolic factors and to discern normal genes from polymorphic genes. RESULTS: According to the genotype frequency and allele frequency analysis, there were no statistically significant differences between IL-1beta, CaSR, and urokinase genes. Also, the analysis between genotypes and metabolic factors did not show statistically significant differences between the three genes. CONCLUSIONS: In Korean urolithiasis patients, IL-1beta, CaSR, and urokinase gene polymorphisms do not differ from those of healthy individuals. A larger-scale study is needed to confirm the need for other genetic markers of urolithiasis.

Erratum: Interleukin-1beta, Calcium-Sensing Receptor, and Urokinase Gene Polymorphisms in Korean Patients with Urolithiasis

No abstract available.

Evaluation of the MicroScan MICroSTREP Plus Antimicrobial Panel for Testing beta-Hemolytic Streptococci and Viridans Group Streptococci / 대한진단검사의학회지

BACKGROUND: In order to determine the clinical usefulness of the MicroScan (Siemens Healthcare Diagnostics, USA) MICroSTREP plus antimicrobial panel (MICroSTREP) for testing antimicrobial susceptibility of beta-hemolytic streptococci (BHS) and viridans group streptococci (VGS), we compared the accuracy of MICroSTREP with that of the CLSI reference method. METHODS: Seventy-five BHS and 59 VGS isolates were tested for antimicrobial susceptibility to ampicillin, penicillin, cefotaxime, meropenem, erythromycin, clindamycin, levofloxacin, and vancomycin by using MICroSTREP and the CLSI agar dilution method. RESULTS: The overall essential agreement with regard to minimum inhibitory concentrations (MICs) (within +/-1 double dilution) between MICroSTREP and the CLSI reference method was 98.2%, and categorical agreement (CA) was 96.9%. For the BHS isolates, the CA for erythromycin was 96.0%, whereas that for cefotaxime, meropenem, levofloxacin, and vancomycin (for ampicillin, penicillin, and clindamycin; 98.7%) was 100%. For the VGS isolates, the CA for penicillin was 84.7% and that for erythromycin, clindamycin, and vancomycin (for meropenem, 86.5%; for ampicillin, 88.1%; and for cefotaxime and levofloxacin, 96.6%) was 100%. All categorical errors of penicillin and ampicillin in the VGS isolates were minor. CONCLUSIONS: The accuracy of MICroSTREP is comparable to that of the CLSI reference method, suggesting that this panel can be effective for testing antimicrobial susceptibility of BHS and VGS.

Prevalence and Antimicrobial Susceptibility of Campylobacter coli Isolates from Swine

Swine is a common source of Campylobacter coli human gastroenteritis, for the treatment of which erythromycin and fluoroquinolones are recommended. The prevalence of antimicrobial-resistant C. coli differs significantly depending on countries. We investigated the prevalence of C. coli in swine from a farm in Buan-gun, Korea in 2010, and determined antimicrobial susceptibility of the isolates. Rectal swab specimens were used to inoculate Campylobacter Preston media and incubated microaerophilically at 42degrees C for 48 h. The species were identified by phenotypic tests and by detecting hipO and glyA genes. PCR was used to detect mutations of A2074C in 23S rRNA gene, and quinolone resistance-determining region (QRDR) of gyrA, which are associated with high level resistance to erythromycin, and with ciprofloxacin, respectively. Antimicrobial susceptibility was determined by the disk diffusion and agar dilution tests. Of the 100 specimens, 55 (55%) yielded C. coli, and 23 of them (41.8%) had A2074G mutation. A2074G mutated isolates showed the lowest MIC90 of imipenem, while those of ampicillin and clindamycin were relatively low. The majority of both A2074G mutation-positive and -negative isolate were susceptible to ampicillin, cefotaxime, and chloramphenicol. All isolates were resistant to ciprofloxacin, and had mutation in QRDR of gyrA. In conclusion, C. coli was detected in 55% of swine, and A2074G mutation was detected in 41.8% of the isolates. All isolates had gyrA mutation-mediated ciprofloxacin resistance.

Evaluation of the Diagnostic Performance of the AdvanSure TB/NTM Real-Time PCR Kit for Detection of Mycobacteria / 대한임상미생물학회지

BACKGROUND: The AdvanSure TB/NTM real-time PCR kit (AdvanSure) was newly developed in Korea to detect Mycobacterium tuberculosis and nontuberculous mycobacteria (NTM) utilizing a specific primer and TaqMan probe targeting the IS6110 and rpoB genes which are unique to these species. The purpose of the present study was to evaluate the clinical utility of AdvanSure by comparing the results of acid-fast staining, mycobacteria culture, COBAS Amplicor MTB PCR (Amplicor), and AdvanSure. METHODS: A total of 182 specimens (105 respiratory and 77 nonrespiratory specimens) were obtained from 165 patients, and acid fast bacilli (AFB) staining, mycobacteria culture, and Amplicor were performed on all specimens. AdvanSure was also performed on the above specimens using the SLAN real-time PCR detection system. The sensitivity and specificity of AdvanSure were analyzed using AFB staining and culture. RESULTS: Of the 182 specimens, M. tuberculosis was detected in 43 specimens and NTM was detected in 12 specimens according to PCR and/or culture. The sensitivity and specificity of the AdvanSure based on AFB culture were 97.3% (36/37) and 95.5% (127/133) in M. tuberculosis and 75.0% (9/12) and 100% (0/133) in NTM, respectively. CONCLUSION: AdvanSure could be useful for detecting M. tuberculosis and NTM in the clinical laboratory with high sensitivity and specificity.

Comparison of ATB FUNGUS 2 and VITEK-2 Antifungal Susceptibility (AST-YS01) Tests for Candida Species Isolated from Blood Culture / 대한임상미생물학회지

BACKGROUND: The VITEK-2 yeast susceptibility test (AST-YS01; bioMerieux, Hazelwood, MO, USA) has recently been introduced as a fully automated, commercial antifungal susceptibility test system that determines MIC endpoints spectrophotometrically, thereby eliminating subjective errors. We compared the ATB FUNGUS 2 (bioMerieux) and VITEK-2 (AST-YS01) systems to the CLSI M27 method for susceptibility testing of Candida isolates. METHODS: We tested 59 Candida species that were isolated from blood cultures at Wonju Christian Hospital between September 2008 and August 2009. We compared MIC results for amphotericin B, flucytosine, fluconazole and voriconazole using the ATB FUNGUS 2 and VITEK-2 (AST-YS01) tests to those obtained by the CLSI M27 broth microdilution method. RESULTS: Within two-fold dilutions of MICs, the agreement of the ATB FUNGUS 2 and VITEK-2 (AST-YS01) tests with the CLSI method according to antifungal agents were: amphotericin B, 100% vs. 100% flucytosine, 100% vs. 100% fluconazole, 83.6% vs. 98.3% and voriconazole, 83.6% vs. 96.7%, respectively. The categorical discrepancies for fluconazole and voriconazole were 20.4% and 18.6% for ATB FUNGUS 2, and 6.8% and 0% for VITEK-2 (ASTYS01). There were no major errors for fluconazole and voriconazole in either ATB FUNGUS 2 or VITEK-2 (AST-YS01) tests. CONCLUSION: The VITEK-2 system (AST-YS01) appears to be rapid and highly correlative with the CLSI method, suggesting that it is effective for antifungal susceptibility testing for Candida species in clinical settings.

In vitro Antibacterial and Morphological Effects of the Urushiol Component of the Sap of the Korean lacquer tree (Rhus vernicifera Stokes) on Helicobacter pylori

Eradication regimens for Helicobacter pylori infection have some side effects, compliance problems, relapses, and antibiotic resistance. Therefore, alternative anti-H. pylori or supportive antimicrobial agents with fewer disadvantages are necessary for the treatment of H. pylori. We investigated the pH-(5.0, 6.0, 7.0, 8.0, 9.0, and 10.0) and concentration (0.032, 0.064, 0.128, 0.256, 0.514, and 1.024 mg/mL)-dependent antibacterial activity of crude urushiol extract from the sap of the Korean lacquer tree (Rhus vernicifera Stokes) against 3 strains (NCTC11637, 69, and 219) of H. pylori by the agar dilution method. In addition, the serial (before incubation, 3, 6, and 10 min after incubation) morphological effects of urushiol on H. pylori were examined by electron microscopy. All strains survived only within pH 6.0-9.0. The minimal inhibitory concentrations of the extract against strains ranged from 0.064 mg/mL to 0.256 mg/mL. Urushiol caused mainly separation of the membrane, vacuolization, and lysis of H. pylori. Interestingly, these changes were observed within 10 min following incubation with the 1 x minimal inhibitory concentrations of urushiol. The results of this work suggest that urushiol has potential as a rapid therapeutic against H. pylori infection by disrupting the bacterial cell membrane.